The flow of cooled air from a duct to a space to be cooled is commonly controlled by way of a variable volume, air distribution terminal. In such a unit, an inflatable bellows or bladder damper typically cooperates with a cut-off plate to define an air flow passage whose width varies inversely with the degree of inflation of the bellows. The degree of bellows inflation is, in turn, controlled in response to the load in the space to be conditioned.
In order to maintain the desired volumetric flow from the terminal, it is important that the air flow passage width be uniform along the entire length of the terminal. It is also important that the air flow passage defining structure be uniform along its entire length such that when the terminal is open, the flow passage width is uniform along its length, and when the terminal is closed, the flow passage is closed along its entire length such that no leakage occurs. Further, it is important that the sound resulting from the flow of air from such a terminal be minimized.
Consideration was given to the above described requirements in the apparatus shown and described in U.S. Pat. No. 4,811,575 assigned to the assignee of the present invention. Here, a foam material was used between the bellows and the cut-off plates to assist in maintaining a proper sealing relationship between the two elements for complete cutoff of air flow when the unit is closed. A foam material was also used, both on the bellows structure and on the cutoff plates, to provide the function of reducing noise caused by the flow of air from the unit. The structure, however, is relatively complex, thereby rendering it relatively expensive, both in terms of material and in time to properly assemble the unit.
It is therefore an object of the present invention to provide a simplified structure for an air terminal.
Another object of the present invention is the provision for an air terminal which controls the flow of air in a uniform and precise manner.
Yet another object of the present invention is the provision for an air terminal apparatus which allows for minimal leakage when in the off condition.
Yet another object of the present invention is the provision in an air terminal for minimizing the noise resulting from the flow of air.
Still another object of the present invention is the provision for an air distribution terminal which is economical to manufacture and effective in use.
These objects and other features and advantages become more readily apparent upon reference to the following description when taken in conjunction with the appended drawings.